Endocrinology Flashcards
Diagnostic test thresholds for diabetes diagnosis
Random plasma glucose
- PreDM 140-199
- DM 200
Fasting plasma glucose
- PreDM 100-125
- DM 126
2-hour OGTT
- PreDM 140-199
- DM 200
HgA1c
- PreDM 5.8-6.4%
- DM 6.5%
Labs to distinguish type 1 from type 2 DM
C peptide
Antibodies:
Anti-insulin antibodies (IAA)
Anti-islet cell cytoplasm antibodies (ICA)
Anti-Glutamic acid decarboxylase antibodies (GAD) -MC
Anti-tyrosine phosphatase antibodies
Precipitating factors for DKA
Undiagnosed diabetes Missed insulin doses Infection - PNA, gastroenteritis, UTI Severe medical illness - MI, stroke, bowel ischemia Trauma Medications - glucocorticoids alcohol or drug abuse Pancreatitis
DKA - features and diagnosis
Features: Weakness Polyuria and polydipsia Abdominal pain, nausea, vomiting Altered mental status -> coma Kussmaul breathing - deep, labored, fast Fruity order on breath Dry mucous membranes low skin turgor
Dx:
Glucose 200-600
High anion gap metabolic acidosis - ABG, BMP
Serum/urine ketones
Sodium +/- pseudohyponatremia
Potassium looks high - low total body K, excreted in urine
Treatment of DKA
Admit to ICU
IVF - NS or LR - large boluses - esp hypotension
IV insulin
Add IV glucose when glucose less than 200
Electrolyte management: potassium above 4, magnesium above 2, phosphorus, calcium
Identify and treat any precipitating factors
Wait until anion gap closes to stop insulin - bridge to subcutaneous insulin for maintenance
DKA vs HHS
DKA: T1DM Glucose over 200 pH less than 7.3 ketones present High anion gap Normal/variable plasma osmolality
HHS: T2DM Glucose over 600 pH >7.3 small or absent ketones normal/variable anion gap
Plasma osmolality >320 (high)
Hyperosmolar hyperglycemic non-ketotic state
Features:
Polyuria and polydipsia
Dehydration
AMS, seizures, stroke, coma
Dx:
Glucose >600-800
No acidosis
elevated plasma osmolality (>320)
Tx: Admit to ICU IV insulin Correct electrolytes Identify and treat underlying disorder
End treatment: normalized glucose and osmolality
Nonproliferative diabetic retinopathy
Cotton wool spots
Hard exudates
Microaneurysms
Tortuous vessels
Tx: if severe - panretinal photocoagulation PRP
Surveillance and blood glucose and BP control
Proliferative diabetic retinopathy
Neovascularization - fragile new vessels prone to hemorrhage Cotton wool spots Hard exudates Hemorrhage AV nicking Edema
Tx: PRP VEGF inhibitors Intravitreal corticosteroid Vitrectomy (if vitreous hemorrhage)
Diabetic nephropathy
Microalbuminemia ->
Overt proteinuria ->
Nephrotic syndrome and/or Progressive kidney dysfunction
-Kimmelstiel-Wilson nodules on pathology
-> hemodyalsis
Tx: prevention - ACE/ARB
Diabetic neuropathy
Sensory:
- Progressive stocking/glove distribution
- paresthesias, dysesthesias, or numbness
- prevention of injury and infection is paramount
Motor
- poor coordination
- weakness
Autonomic
- erectile dysfunction
- postural hypotension
- incontinence
- gastroparesis (tx erythomycin, metoclopramide)
Tx:
Gabapentin, carbamazepine, pregabalin - nerve pain
TCAs, duloxetine
Narcotics, tramadol last resort
Goal: avoid injury/infection
Complications
Charcot joints - chronic progressive arthropathy
-associated with tabes dorsalis and diabetes
DM preventive care
HbA1c q3 mo -> q6 if stable at goal
urine microalbumin:cr ratio - over 300, get 24 hr urine
lipids q1 yr
-treat with mod-high intensity over 40
Complications from bypass surgery
Deficiencies of iron, B12, folate, thiamine, vitamin D
Dumping syndrome - bloating, swelling, cramping
GERD
Vomiting
Criteria for metabolic syndrome
Abdominal obesity Elevated triglycerides Low HDL Elevated blood pressure Abnormal blood glucose
Symptoms of hypoglycemia
Adrenergic symptoms (elevated epi) Faintness Weakness Anxiousness Sweating Palpitations -beta blockers can mask the symptoms
neuroglyopenic symptoms Headache Confusion Mental status changes Seizure Loss of consciousness
Whipple’s Triad
Symptoms of hypoglycemia - especially after fasting or heavy exercise
Low plasma glucose - below 45 at time of symptoms
Relief of symptoms when the glucoses raised to normal
Reactive hypoglycemia
Excessive insulin production in response to the amount of blood glucose present
Occurs 1-3 hours after a high carb meal
Dx: mixed meals tolerance test instead of fasting to induced hypoglycemia
after gastric bypass or in prediabetes
Encourage high protein and less junk food
Insulinoma
Insulin secreting tumor are usually in the pancreas
Hypoglycemia while fasting
Get imaging CT/MRI to localize
Surgery if tumor identified
Diazoxide - inhibits insulin secretion
Octreotide
Secondary hypoglycemia to other disease
Liver disease, Malnutrition, adrenal insufficiency
Hypoglycemia during fasting
Dx: Check LFTs Markers of nutrition Cortisol stimulation test ACTH level
Alcohol induced hypoglycemia
Decreased gluconeogenesis - NADPH used up to metabolize alcohol
Hypoglycemia with fasting
Check the blood alcohol level
Give thiamine before glucose to prevent Wernicke encephalopathy
Thyrotropin releasing hormone (TRH)
Released from the hypothalamus
Stimulates TSH from pituitary
Thyroid stimulating hormone (TSH)
Released from pituitary gland
Stimulates the thyroid directly
Best test for thyroid function
Elevated in hypothyroidism
Changes exponentially with small changes in T4/T3
Thyroxine (T4)
Thyroid hormone
Replace to therapeutically in hypothyroidism
Half-life 7 to 10 days
Measure free T4 level
Low in hypothyroidism
Triiodothyronine (T3)
Thyroid hormone mostly produced in peripheral tissues
High affinity for receptor
Short half-life
Measure free T3 level
low in hypothyroidism
Thyroid binding globulin (TBG)
Protein that binds circulating T4 and T3
High in pregnancy and OCP use (high estrogen states)
Low in liver failure and nephrotic syndrome (low-protein states)
Amount of TBG affects total T4 and T3 levels, but not free levels
Thyroid peroxidase antibody (TPO)
Causative antibody (others: antithyroglobulin and antimicrosomal) in Hashimoto’s thyroiditis
Used to Determine cause of hypothyroidism
Causes of hypothyroidism
Congenital hypothyroidism Hashimoto's thyroiditis Iodine deficiency or excess Subacute granulomatous thyroiditis (de Quervain) Riedel's thyroiditis Neck radiation - including treatment for hyperthyroidism with radioactive iodine Surgical removal of the thyroid Idiopathic causes
Medications:
Amiodarone - lots of iodine
Lithium
Tyrosine kinase inhibitors (imatinib)
Clinical features and treatment for hypothyroidism
Features: Cold intolerance Weight gain Fatigue Constipation Voice hoarseness or change Menorrhagia Slowed mental or physical function Dry skin with coarse brittle hair Reflexes - slow return phase
Tx:
Levothyroxine - T4
Synthetic T3
Natural thyroid replacement - dosing inconsistencies
Hashimoto thyroiditis
Women - teens and middle age
Euthyroid state early in disease
Thyrotoxicosis d/t inflammation and destruction of follicle cells
-> painless goiter, hypothyroid
Dx:
Elevated total and LDL cholesterol - recovers as treated
Thyoid peroxidase (TPO), antithyroglobulin and antimicrosomal Abs
Tx: thyroid hormone replacement
Subacute thyroiditis
Features: PAINFUL goiter neck pain Fever Elevated ESR Low uptake on thyroid scan
Cause hyper or hypothyroidism
Tx: NSAIDS, steroids - pain replace thyroid hormone if hypo Bet-blockers if hyper continue to monitor thyroid levels
Riedel’s Thyroiditis
Young
Fixed, hard, rock like, painless thyroid
Fibrosis extends into adjacent structures
Euthyroid or hypothyroidism
Congenital hypothyroidism
Causes:
Sporadic thyroid dysgenesis
Severe iodine deficiency
Hereditary disorder of the thyroid hormone synthesis
Features: Lethargy Poor feeding Thick, protruding tongue Constipation Umbilical hernia Moderate to severe intellectual disability Maternal hormones can cross placenta - normal intrauterine development
Dx:
Newborn screen TSH
Tx: replace hormone
